Evolution is generally seen as a response system to the environment. For example, it gets cold so an species is selected for a thicker coat. The genes needed for this would be created by random mutations.

My question is why, if mutations are what cause these changes, there was no evolution of lifeforms for 2 billion years after blue-green algae appeared 2.6 billion years ago. Even if the physical environment was stable, would there not have been other factors such as competition that, coupled with mutation, would have formed a new kind of life form. Considering the relatively short/recent diversification of life, it seems unlikely that, following the current interpretation of evolutionary processes, that no new life forms would have formed in such a long period of time.

Sorry for the vagueness of the question, any thoughts or links to relevant papers would be appreciated.

of which no one has ever observed a fish bring forth anything other than a fish. If someone wants to believe by faith that contrary to every observed law of nature in written history a fish can bring forth something other than a fish that is their own personal religion and has NO basis in science. For people at uni ask your professors for LITERATURE of a mutation adding NEW genetic information (NEW nucleotides for NEW protein), neofunctionlization is a myth for the most part but see if he gets angry or if he actually can cite something (100% can NOT).

Well recorded history only reaches back as far as 4th millennium BC. Evolution requires a much longer time period. Besides even in recorded history there is evidence for evolution such as the domestication of animals. They are still the same organism, but have changed even in the this small time period.

You are welcome to your view but i didn't create this thread to argue whether or nor evolution exists.

Dayren, what do you mean by there was no evolution of organisms during that time?

As far as I understand, there has been evolution of organisms basically whenever there first was competition for resources or space to live, which would be pretty soon after life emerged (local competition would happen almost instantly on the evolutionary time scale).

However, most of the "tools of the trade" of more complex organisms were yet to evolve (such as enzymes for oxidative energy metabolism and many others), so there could not be advanced organisms for this long time. The atmosphere of that time could not support very complex life forms and it did not drive the evolution towards oxygen-based life, unlike the oxygen-rich atmosphere created by the blue-green algae did later. That is why most of the early eukaryotes appeared only after the oxygenation of the atmosphere around 2 billion years ago and this finally sped up the rate of speciation to a completely new level.

I mean that, like you said, complex organisms didn't evolve for a long time. If there was a sudden evolution into complex life, why did it happen in the first place? Surely the simple life forms that evolved into the more complex life forms would have benefited more in terms of survival by remaining as simple organisms. And why weren't the conditions previously suitable for complex life? Yes, today's complex organisms could not survive in such conditions, but if evolution sees complex life as an advantage surely it would have found a way to form complex organisms suited to the harsh conditions.

dayren wrote:I mean that, like you said, complex organisms didn't evolve for a long time. If there was a sudden evolution into complex life, why did it happen in the first place? Surely the simple life forms that evolved into the more complex life forms would have benefited more in terms of survival by remaining as simple organisms. And why weren't the conditions previously suitable for complex life? Yes, today's complex organisms could not survive in such conditions, but if evolution sees complex life as an advantage surely it would have found a way to form complex organisms suited to the harsh conditions.

Its a slow process - evolution HAS found a way to form complex organisms suited to harsh conditions, like Earth's moon for example. Humans. But it takes time. Another aspect of the evolution of complex organisms is the development of sexual reproduction, which allows the existence of large long-lived complex organisms by speeding up the production of diverse genetic material beyond that provided by mutation. All of this takes time, and it took less time for oxygen-emitting organisms to terra-form the Earth and to develop sexual reproduction to evolve than it would have taken for complex mutation-dependent organisms to evolve in the harsh conditions, which might not even be possible.

dayren, you have some misconceptions about evolution. To answer your overall question, yes evolution is an incredibly simple concept. However, the details are more complex but that's what makes it fascinating! Below, I've quoted a few things from your last post and responded to them.

"Surely the simple life forms that evolved into the more complex life forms would have benefited more in terms of survival by remaining as simple organisms."Why would you think that? Anything that allows an individual to reproduce more than its competition will benefit it and lead to its evolution. In general, that means increased complexity but that is not always the case, as shown by cave-dwelling organisms that lost their eyes - they were benefited by saving the energy that went into producing and maintaining eyes that were unneeded. Hence, they had a survival advantage by losing a trait that had once been beneficial

"And why weren't the conditions previously suitable for complex life?"The conditions may have been suitable (I'm not a geologist or paleobiologist) but if there was no complex life with the necessary traits to take advantage of it, it doesn't matter.

"Yes, today's complex organisms could not survive in such conditions"We don't know that for sure and can never know it, since we can't go back in time.

"but if evolution sees complex life as an advantage surely it would have found a way to form complex organisms suited to the harsh conditions."Evolution is directionless in the present. We can look backwards in time and see a direction - e.g., from small dinosaurs without feathers to those with feathers to birds that can fly and back to lack of flight in aquatic penguins. However, we cannot predict (and neither can evolution) what traits will be beneficial in the future. If the traits weren't available, then no organism could take advantage of the conditions.

"Nothing in biology makes sense except in the light of evolution."Theodosius Dobzhansky"Most people who hate the idea of evolution do so because if it was working properly, they'd be dead."Anonymous

dayren wrote:Surely the simple life forms that evolved into the more complex life forms would have benefited more in terms of survival by remaining as simple organisms.

In many cases that is true. The most numerous organisms on the Earth are still the prokaryotes, which in many ways can be said to be "simple" organisms. So one could argue that it is the most effective form of life even in today's world. This is especially true in harsh environments that are short of nutrients or are otherwise inhospitable. In most places, however, it was beneficial to evolve into something more complex just to gain that edge in competition. If you were a bit bigger, faster and meaner than the others, you could, for example, eat the others for lunch. Of course, not everyone can afford to be big and mean, since it requires more energy and nutrients, so there has always been room for tiny, energy-efficient and simple forms of life. The food chain looks like a pyramid largely because of the same reasons (the few apex predators forming the top).

dayren wrote:...but if evolution sees complex life as an advantage surely it would have found a way to form complex organisms suited to the harsh conditions.

Perhaps. Or perhaps not: it is also possible that with the building blocks available on the Earth, the only way to "power up" large and complex organic life forms is to use oxidative metabolism. It is possible that other methods of energy production are simply too ineffective, or if they are effective (like nuclear fission!), they cannot be utilized by cellular metabolism. So it is possible that complex life forms could only emerge after the atmosphere contained enough oxygen. Being able to utilize oxygen gave also an enormous competitive edge because oxygen was most likely toxic to early organisms relying on anaerobic metabolism, but that alone would not drive evolution towards more complex life forms - just towards a switch from anaerobic metabolism to aerobic one. But after this, the new and highly effective means of energy metabolism was available, supporting the growth of new, multicellular life forms.

thoffnagle wrote:"And why weren't the conditions previously suitable for complex life?"The conditions may have been suitable (I'm not a geologist or paleobiologist) but if there was no complex life with the necessary traits to take advantage of it, it doesn't matter.

...

"Yes, today's complex organisms could not survive in such conditions"We don't know that for sure and can never know it, since we can't go back in time.

I have been under the impression that it is commonly accepted view among scientists that the Earth's early atmosphere was a reducing one with no oxygen and thus unable to support multicellular life as we know it. That does not necessarily mean it could not have been able to support any complex life forms, but based on our current knowledge of life the only organisms that could have survived on young Earth were similar to Archaea - prokaryote life forms capable of tolerating extreme conditions and utilizing anaerobic metabolism and uncommon energy resources (that would be too ineffective for any larger organism).

Of course in science you cannot say that you "know" anything with 100% certainty, but as far as I am aware the scientist have a pretty good idea of what the conditions on the young Erath must have been (based on, for example, geological data and our knowledge of other rocky planets in our solar system etc.) and that there are no ongoing major scientific arguments concerning the key topics of our planet's development.

dayren wrote:Evolution is generally seen as a response system to the environment. For example, it gets cold so an species is selected for a thicker coat. The genes needed for this would be created by random mutations.

Wrong!!!

I see this again and again. Evolution is NOT a RESPONSE system. Evolution is OUTCOME or END RESULT of genetic mutation/drift + selective pressure or absence of it (diversification process). If you put a live chicken in the fridge for a long time, it will die. There is no "response to environment", mutations at will, etc. However, if you put a million (billion?) chickens in the fridge - one or two might survive (those that happened to have random required mutations that allow then to withstand the cold). Keep them and their progeny in the fridge for a long time and you get new pure breed variety.

Cat wrote:Evolution is NOT a RESPONSE system. Evolution is OUTCOME or END RESULT of genetic mutation/drift + selective pressure or absence of it (diversification process). If you put a live chicken in the fridge for a long time, it will die. There is no "response to environment", mutations at will, etc. However, if you put a million (billion?) chickens in the fridge - one or two might survive (those that happened to have random required mutations that allow then to withstand the cold). Keep them and their progeny in the fridge for a long time and you get new pure breed variety.

This answer makes me uncomfortable, but before I disagree, how do you distinguish a response system from an outcome system? Is there a test I can apply that will decide this question?

Evolution does not respond to situations, it (through mutations) simply provides possibilities. For example, it the climate gets colder, evolution does not respond by providing fur, feathers, blubber, etc. to insulate against the cold. If there are individuals that are able to withstand the colder temperatures, they will survive better than those that can't. If no individuals of that species can tolerate the cold,the species goes extinct.

"Nothing in biology makes sense except in the light of evolution."Theodosius Dobzhansky"Most people who hate the idea of evolution do so because if it was working properly, they'd be dead."Anonymous